1 Technical Field
This invention relates to a volume adjuster and is preferably applicable to a television receiver that can capture terrestrial television transmission signals to a plurality of channels for terrestrial television broadcasting or external image and sound signals supplied from an outside appliance and output a program image and sound on the basis of the terrestrial television transmission signals or an external image and sound on the basis of the external image and sound signals for an audience.
2 Background Art
Signal levels of terrestrial television sound signals included in terrestrial television signals and signal levels of outside sound signals included in outside image and sound signals are different. When an output is switched from an outside image and sound to a program image and sound, or when an output is switched from a program image and sound to an outside image and sound, conventional television receivers match the volume of a program sound on the basis of terrestrial television sound signals and the volume of an outside sound on the basis of outside sound signals by matching the signal level of the outside sound signals with that of the terrestrial television sound signals to output an outside image and sound on the basis of outside image and sound signals (For example, refer to Patent reference 1)
Patent Reference 1 Japanese Patent Laid-Open No. 11-355684 (Page 4 and FIG. 1)
As the television receivers with the abovementioned configuration matches the signal level of outside sound signals with that of terrestrial television sound signals, a range from the minimum to the maximum of an adjustable volume of an outside sound on the basis of the outside sound signals within a predetermined volume control range is matched with a range from the minimum to the maximum of an adjustable volume of an program sound on the basis of the terrestrial television sound signals within the volume adjustable range.
This leads a problem in that a volume of a program sound or an external sound cannot be controlled to suit a user's preference within a volume control range from the desired minimum to the desired maximum in the abovementioned television receivers.